The Anatomy of the Young Protostellar Outflow HH 211: Strong Evidence for CO v = 1-0 Fundamental Band Emission from Dense Gas in the Terminal Shock

Autor(en)

Achim Tappe, J. Forbrich, S. Martín, C. J. Lada

Abstrakt

We present Spitzer Space Telescope 5-37 µm spectroscopic mapping observations toward the southeastern lobe of the young protostellar outflow HH 211 (part of IC 348 in Perseus, 260 pc). The terminal shockof the outflow shows a rich atomic and molecular spectrum with emissionlines from OH, H2O, HCO+, CO2,H2, HD, [Fe II], [Si II], [Ne II], [S I], and [Cl I]. The spectrum also shows a rising continuum towards 5 µm, which we interpret as unresolved emission lines from highly excited rotational levels of the CO v=1-0 fundamental band. This interpretation is confirmed by a strong excess flux observed in the Spitzer IRAC 4-5µm channel 2 image.We also observed the terminal outflow shock of this lobe with the Submillimeter Array (SMA) and detected pure rotational emission from CO2-1, HCO+ 3-2, and HCN 3-2. The rotationally excited CO traces the collimated outflow and the terminal shock, whereas the vibrationally excited CO seen with Spitzer follows the continuation ofthe collimated outflow backbone in the terminal shock. The extremely high critical densities of the CO v=1-0 rovibrational lines indicate terminal shock jet densities larger than 107 cm-3.The unique combination of mid-infrared, submillimeter, and previous near-infrared observations allow us to gain detailed insights into the interaction of one of the youngest known protostellar outflows with its surrounding molecular cloud. Our results help to understand the natureof some of the so-called `green fuzzies’ (Extended Green Objects) identified by their Spitzer IRAC channel 2 excess and association with star-forming regions. They also provide a critical observational test to models of pulsed protostellar jets.

Organisation(en)

Institut für Astrophysik

Externe Organisation(en)

Harvard-Smithsonian Center for Astrophysics, European Southern Observatory (Germany)

Journal

Bulletin of the American Astronomical Society

Band

43

Seiten

2011

ISSN

0002-7537

Publikationsdatum

05-2011

Peer-reviewed

Ja

ÖFOS 2012

103004 Astrophysik

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/the-anatomy-of-the-young-protostellar-outflow-hh-211-strong-evidence-for-co-v--10-fundamental-band-emission-from-dense-gas-in-the-terminal-shock(05a2ff47-eedb-4e5a-a744-8beeb2cb0b64).html